Research on high-speed data acquisition system of negative ion source breakdown

Abstract

During the long pulse discharge experiment of negative ion source, the risk of breakdown increases significantly. Current data acquisition system applied on the negative ion source based neutral beam injection (NNBI) is low-speed and lacks of the ability to accurately collect and characterize the electrical signals at the moment of breakdown, which makes it difficult for researchers to analyze the cause of breakdown. To solve this issue, a high-speed data acquisition (DAQ) system using random trigger method, pre-trigger method, multithreading and MDSplus database is researched and designed to collect electrical signals during breakdown specifically. Random trigger instructs the system to start data acquisition when the breakdown signal arrives, pre-trigger method helps acquire samples for a period of time before the breakdown signal arrives, multithreading enables multi-channel data acquisition, MDSplus database realizes remote data storage and timeline synchronization with other data acquisition systems. With this design, it is possible to obtain accurate electrical signals of breakdown and make significant savings in storage costs at the same time.